几道计算题,快.计算：（-2a)^2/a=(9x^4-6x^3)/3x^2=(1.8*10^12)/(6*10^5)=分

计算：（-2a)^2/a= 4a
(9x^4-6x^3)/3x^2= 3x^2 - 2x
(1.8*10^12)/(6*10^5)= 3 * 10^6
分解因式：2x^2-12x+18= 2 (x-3)^2
化简：a-b/a^2-b^2= 1/(a+b)
约分：x^2+2x-3/9-x^2= (x-1)/(3-x)
化简求值：2x^3+4x-1/3x^2-(x+3x^2-2x^3),其中x=-3
4x^3+3x-3x^2-1/3x^2 = x (4x^2-3x+3)-1/3x^2
= (-3)*(36+9+3)-1/27 =- 144 - 1/27
计算：（6x^3y^2)^2*(-1/3xy^2)^3/(8/3x^7y^10)
= (36x^6y^4) * (3x^7y^10)/ [8 * (27x^3y^6)]
= (4 * 9 * 3 * x^13 * y^14)/( 8 * 27 * 3x^3y^6)
= x^10y^8/2
计算：(a-b)^3*(-a+b)^2/(b-a)^4
= (a-b)^3 * (a-b)^2 / (a-b)^4
= (a-b)
计算：（2x^3y^3-6x^2y+4xy^2)/[(-2x)*(-y)]
= 2xy * (x^2y^2-3x+2y)/(2xy)
= x^2y^2-3x+2y
化简：a^2+ab-2b^2/a^2+2ab+2b+a = [(a-b)(a+2b)]/[(a+1)(a+2b)]
= (a-b)/ (a+1)
x^2-3x+2/x^2-6x+5= [(x-1)(x-2)]/[(x-1)(x-5)]=(x-2)/(x-5)
不改变分式的值,把下列各式的分子与分母各项系数化为整数
0.5x-0.07y/3x+2y = x/2 - 7y/300x +2y
(a+1/4b)/(3/4a-2b) = (4a+b)/(3a-8b)

同上